In the past, solid-state image pickup devices such as a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor are used in an electronic apparatus having an imaging function such as a digital still camera and a digital video camera. The solid-state image pickup device has a pixel in which a photodiode (photoelectric conversion device) that performs photoelectric conversion and a transistor are combined, and an image is constructed on the basis of pixel signals output from a plurality of pixels arranged in a plane.
For example, in the solid-state image pickup device, charges stored in the photodiode (PD) are transferred to an FD (floating diffusion) portion having a predetermined capacitance provided at a connection portion between the PD and a gate electrode of an amplification transistor. Then, a pixel signal corresponding to the amount of charges stored in the FD portion is read from the pixel, is subjected to AD conversion by an AD (Analog Digital) conversion circuit having a comparator, and output.
Further, in recent years, a technology of detecting a phase by using a part of pixels of a CMOS image sensor to improve the AF (autofocus) speed, so-called image plane phase difference AF, has become widespread. Examples of a system of the image plane phase difference AF include a PD division system (see, for example, Patent Literature 1). In the PD division system, the PD of the pixel is divided into a plurality of parts, phase information is generated on the basis of pixel signals acquired by each of the divided PDs, and distance measurement is performed on the basis of the phase information.